As of 1st January 2014 The Suez Canal Authorites (SCA) has increased the charge of an imposed tug to SDR 22,000

SCA Circular 03/2004 shall be considered null and void, and is replaced by the following :
Imposed tugboats are hired at a unified rate of SDR 22,000 for the entire trip of the tugboats from one end of the Canal to the other .

You can find the new circular 7/2013 here

Art. 57 – Cases of Imposed Tugs :

The CA may require any vessel to take a tug or tugs through the Canal, when in its judgment such action is necessary to ensure safety of the vessel or to the Canal.

Any vessel without mechanical power, or the machinery of which is/or becomes disabled, or steers badly, or which is liable to become unmanageable for any reason, shall be towed through the Canal.

Vessels having engine or steering gear trouble for the second time during the same passage. Bad view vessels owing to deck cargo, containers, cranes or constructions impeding the view from the wheelhouse and wings.

a – Vessels of 1500 SC.G.T and over unable to use one or both their bow anchor. (Ref. Art: 23)
b – Vessels of 1500 SC.G.T and over built with one anchor.
c – Vessels of 1500 SC.G.T and over built with more than one anchor if only one of them on the bow
d – Special cases to be studied.

Drilling vessels.

Vessels with two engines on one propeller of which one is out of order for any reason and can not maintain speed of 10 knots at least without current after sea trial to assure the speed and valid sea worthiness certificate.

Vessels with two engines on two propellers of which one is out of order On Master’s request for one tug or more.

On Master request for one tug or more.

Submarines to be escorted by one or two imposed tugs according to CA. Survey (depending on submarine condition, anchors, mooring facilities, power drive…. etc).

Air craft carriers to be escorted by two imposed tugs.

a) General Cargo vessels carrying explosive of type class 1, (explosive div.1.1 , div.1.2 , and div.1.3 according to IMDG code) in less than 50% of the loaded cargo, an imposed tug to be added during transit, for security.

b) But if the explosive cargo are 50% or more of the loaded cargo, two imposed tugs are to be added during transit, for security.